The 14.5ÃÂ114 mm (.57 calibre) is a heavy machine gun and anti-materiel rifle cartridge used by the Soviet Union, the former Warsaw Pact, modern Russia, and other countries.
It was originally developed for the PTRS and PTRD anti-tank rifles, and was later used as the basis for the KPV heavy machine gun that formed the basis of the ZPU series anti-aircraft guns that is also the main armament of the BTR series of armoured personnel carriers from the BTR-60 to the BTR-80 and for heavy anti-materiel sniper rifles.
The 14.5 ÃÂ 114 mm has 42.53 ml (655 grains H<sub>2</sub>O) cartridge case capacity. The exterior shape of the case was designed to promote reliable case feeding and extraction in bolt-action rifles, semi-automatic rifles, and heavy machine guns alike, under extreme conditions.
14.5 à114 mm maximum cartridge dimensions. All dimensions in millimetres (mm), but angles may be measured in degrees or degrees-arcminutes-arcseconds (ð ); alpha is 22.5ð.
Americans define the shoulder angle at alpha/2 = 22.25ð. The most common rifling twist rate for this cartridge is 1 in , with 8 grooves, land â , and groove â . Assuming a muzzle velocity of , as is roughly typical for it, this gives it a muzzle angular frequency of â (; ). According to the official guidelines, the 14.5 à114 mm case can handle up to 360 MPa (52,213 psi) piezo pressure. In C.I.P. regulated countries every rifle cartridge combo has to be proofed at 125% of this maximum C.I.P. pressure to be certified for sale to consumers.
Cartridges use lacquered steel cases and percussion primers. Some countries also use brass cartridge cases. The propellant consists of smokeless powder with seven tubes, designated as "5/7NA powder". Two different versions of bullet series are known, the earlier has a conventional bullet jacket with a boat-tail. These have a long engraving portion that causes considerable barrel wear. The newer bullet types have a smaller engraving portion with a rounder boat-tail and were used from about 1957 onward.
The cartridge has been manufactured in Bulgaria, China, Egypt, Hungary, Iraq, North Korea, Poland, Romania, Russia, and the former Czechoslovakia. There are new Chinese armour-piercing types:
Anti-materiel rifles
Machine guns
Other
In addition to being chambered in multiple calibers, the Ukrainian Horizon's Lord rifle uses its own proprietary "12.7 ÃÂ 114 HL" cartridge made by necking down a 14.5 ÃÂ 114 mm cartridge case to accept a .50 BMG bullet. In essence, the 14.5 ÃÂ 114mm cartridge is the parent case for the 12.7 ÃÂ 114 HL.